EP0487140A1
Expired / Lapsed
EP
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Active matrix liquid crystal display systems and methods of operating such systems
Assignee: Philips Electronics UK Ltd
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Filing: 1991-11-12
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Granted: —
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Expires: 2011-11-12
Abstract
Abstract An active matrix liquid crystal video display system comprises a display panel (10) having a row and column matrix array of liquid crystal picture elements (12) with respective controlling switching devices (11) for displaying video information such as TV pictures, and a drive circuit for driving the picture elements to which a video, e.g. TV, signal of given field frequency is supplied (25). In order to reduce the response time of the picture elements, the display panel is driven at a field rate higher than that of the supplied video signal. To this end, the drive circuit includes a field rate conversion circuit (28,30,31,32) comprising field stores.
Inventors
- 👤 Alan George Knapp
- 👤 John Revere Mansell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:43
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/36; G09G3/3611; G09G3/3648; G09G2320/00; G09G2320/02; G09G2320/0247; G09G2320/0252; G09G2340/00; G09G2340/04; G09G2340/0407; G09G2340/0435
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
97 words
A method of reducing picture element response time of an active matrix liquid crystal display system comprising a liquid crystal display panel having a row and column array of picture elements each associated with an active switching device, and drive means for driving the picture elements according to a video signal of a given field rate supplied to the drive means, characterised in that the picture elements of the panel are driven at a field rate higher than that of the video signal supplied to the drive means thereby reducing the response time of the picture elements.
Claim 2
Dependent Claim
36 words
A method according to Claim 1, characterised in that the field rate of the display panel is n times the field rate of the input video signal where n is equal to 2, 3 or 4.
Claim 3
Dependent Claim
53 words
A method according to Claim 1 or Claim 2, characterised in that video signal fields are supplied to field store means whose contents are read out to a column drive circuit of the drive means at a rate higher than that at which the video signal is loaded into the field store means.
Claim 4
Dependent Claim
25 words
A method according to Claim 3, characterised in that the field store means operates to provide a sequence of display fields which includes repetition fields.
Claim 5
Dependent Claim
116 words
An active matrix liquid crystal video display system comprising a display panel having a row and column array of liquid crystal picture elements each associated with a switching device, input means for receiving a video signal of a given field frequency and drive means for driving the picture elements to produce an output according to the video signal, the picture elements being driven a row at a time by repetitively scanning the rows in sequence, characterised in that the drive means comprises means for reducing picture element response time which is operable to drive the picture elements at a field rate greater than that of the input video signal thereby to reduce picture element response time.
Claim 6
Dependent Claim
46 words
An active matrix liquid crystal video display system according to Claim 5, characterised in that the drive means is arranged to drive the display panel at a field rate n times that of the input video signal where n is equal to 2, 3 or 4.
Claim 7
Dependent Claim
74 words
An active matrix liquid crystal video display system according to Claim 5 or 6, characterised in that the input means is connected to field store means into which video signal fields are loaded and whose output is connected to a column drive circuit of the drive means, the field store means being operable such that the contents are read out at a rate faster than that at which the video signal fields are loaded.
Claim 8
Dependent Claim
34 words
An active matrix liquid crystal video display system according to Claim 7, characterised in that the field store means is operable to provide at its output a sequence of display fields including repetition fields.
References Cited (Backward Citations)
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